Telephony equipment is commonly used to establish voice and data communications between served locations over a telephone network. Typically, the voice and data are transmitted between served locations through one or more central offices. Telephony equipment located at a central office will be referred to herein as switching equipment. Telephony equipment located at a served location will be referred to herein as a telephone device. A telephone device can be any device capable of communicating over the telephony network; telephone devices include analog telephones, PBX systems, digital telephone systems, computers, facsimile machines, and the like.
The present invention relates primarily to telephone devices used to communicate over a telephone network using audio signals, and that application will be described in detail below. An audio telephone typically includes a keypad and electronics for generating tones based on entries made on the keypad. When a connection is to be established between a source telephone and a destination telephone, the number of the destination telephone is entered using the keypad, although the keypad function may be automated using what is commonly referred to as speed dial. The source telephone transmits the number of the destination to telephone to the switching equipment at the central office as a sequence of audible tones. The switching equipment converts the sequence of tones into the destination telephone number and establishes an appropriate connection between the source and destination telephones.
To be recognized by the switch equipment, telephone devices is typically generate tones referred to as DTMF signals. DTMF signals comprise first and second sine wave signals that are added together. A predetermined DTMF matrix relates the frequencies of the first and second sine wave signals with the numerical value associated with each DTMF signal. The switching equipment filters the DTMF tones to obtain the individual sine wave signals, determines the frequencies of thereof, and looks up the value associated with each DTMF tone in the DTMF matrix.
Conventionally, the frequency of the low frequency signal is one of a first group of four predetermined frequencies, while the frequency of the high frequency signal is one of a second group of four predetermined frequencies. The DTMF signal thus yields sixteen possible combinations of frequency signals. Conventionally, the DTMF signals represent the numerals 0-9, the symbols “*” and “#”. The letters A-D are also represented, but conventional telephone keypads do not have keys corresponding to the letters A-D.
Telephone devices such as computers, facsimile machines, and telephones having speed dial can typically be pre-programmed to automatically generate a sequence of DTMF signals without entering in each digit on the keypad. More specifically, speed dial allows the user to associate a longer telephone number with a dedicated button or shorter combination of numbers. Speed dial capable telephone devices often allow the entry of extensions to a particular telephone number with pauses and other commands necessary to establish the desired connection.
However, many existing telephones do not have speed dial. In addition, even if speed dial is available on a given telephone device, many users do not know how or bother to learn how to use the speed dial features. Speed dial features are thus only available to a limited number of customers who use telephone devices.
Within the United States and Canada, telephony switching equipment is programmed to recognize a ten-digit telephone number. The first three digits of the telephone number are referred to as the area code; the last seven digits are referred to as the local portion. Traditionally, area codes have been associated with a geographic local calling area, and served locations within a given local calling area could connect to each other by transmitting either the local number or the digit “1” plus the local number.
Connections between served locations in different local calling areas require the entry of the entire ten-digit telephone number. Traditionally, calls between served locations in different local service areas involved a long distance carrier and associated long distance charges.
Factors such as the proliferation of cellular telephones, facsimile machines, and other telephone devices have depleted the number of local numbers within many area codes. In each situation where the local numbers within an area code have become depleted, the telephone companies have responded in one of two ways.
First, the traditional geographic calling areas have been broken into smaller regions, each of which has been assigned a new area code. This approach requires the purchase of new or updated switching equipment and is relatively expensive for the telephone companies.
The second approach is to create a new area code for the local service area with a shortage of local numbers. This approach is relatively inexpensive for the telephone company. In addition, calls between served locations having different area codes within a local calling area do not involve a long distance carrier; even though the entire ten-digit number is dialed, users are not required to pay long distance charges.
However, overlaying a new area code in an existing local service area requires users to enter the entire ten-digit telephone number even when dialing within the local calling area. As the number of local numbers with the new area code increases, customers will be forced to learn and remember which of two or more area codes are associated with each local number. In addition, customers will be required to enter the extra three digits associated with the area code each time they enter a local phone number.
While telephone devices having speed dial capabilities can lessen the burden of learning, remembering, and using ten-digit numbers for local dialing, these features are not available to many users as described above. Speed dial is thus only a partial answer to the problems associated with using one or more additional area codes in an existing local calling area.
Accordingly, in many cases adding area codes in an existing local calling area increases the burden on the customer and causes increased customer confusion. Telephone customers and regulatory agencies thus tend to resist or prohibit attempts by telephone companies to overlay new area codes in existing local calling areas.
Generally, the need exists for improved systems and methods of providing speed dialing capabilities to more telephone users. More specifically, the need exists for systems and methods that ease the transition to the use of ten digit telephone numbers within local calling areas.